The top diplomats of Japan, South Korea and the United States agreed in Tokyo on Sunday to strengthen their relations in order to realize the denuclearization of North Korea, dpa reported. US Secretary of State Mike Pompeo, Japanese Foreign Minister Taro Kono and his South Korean counterpart Kang Kyung Wha emphasized the need to urge Pyongyang to take concrete steps toward denuclearization and agreed to maintain UN economic sanctions against the reclusive state. "We were able to reaffirm our unwavering commitment to the continued strengthening of our trilateral cooperation towards the common goal of North Korea's complete, verifiable and irreversible dismantlement of all nuclear weapons and missiles," Kono told a joint news conference following their talks. Their talks come one day after Pompeo's visit to North Korea.